Limited posterolateral surgical approach to the knee for excision of osteoid osteoma

An 18-year-old man suffered four years of undiagnosed knee pain until a CAT scan revealed an epiphyseal osteoid osteoma of the tibia located subchondrally, just medial to the proximal tibiofibular joint. A nidus in this location is not easily accessible, and its proximity to the joint surface raised concerns about damage to the tibial plateau. To facilitate excision of the tumor, cadaveric dissections were performed to develop a limited posterior approach to the proximal, lateral portion of the tibia. The CAT scan was used to calculate the precise dimensions of the tumor and its relation to the posterior tibial cortex and the proximal tibiofibular joint. With the use of the exposure developed in the laboratory and the calculations derived from the CAT scan, the tumor could be excised by removing a single block of bone 15 mm3. Intraoperative radiographs confirmed the presence of the nidus within the excised block of bone. This case report reaffirms the frequent difficulties and tardiness in diagnosing osteoid osteomas and the need to include these tumors in the differential diagnosis of knee pain and epiphyseal lesions. Before CAT scans were used, the working diagnoses were torn meniscus, juvenile rheumatoid arthritis, and bone hemangiomatosis.     

Calciphylaxis – a topical overview

'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis.     

Neurofibroma in a patient with von Recklinghausen's disease seen as a malignant schwannoma. A case report

A rapidly growing, malignant schwannoma occurred in a 46-year-old woman with neurofibromatosis. Computed tomography, isotope bone scan, chest roentgenogram, and angiogram are helpful in determining the local extent and distant spread of such musculoskeletal tumors and are useful in planning appropriate surgical management. A well-planned biopsy, however, is essential to accurately determine the histologic diagnosis of the tumor. Clinical and roentgenographic presentation of some benign lesions may mimic malignant tumors. To confirm the diagnosis of a malignant or benign tumor, it is advisable to examine the musculoskeletal tumor histologically before proceeding with the definitive treatment, even if the clinical presentation strongly suggests malignancy.     

Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy

The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal- specific guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosis, was screened for mutations within this family and in a panel of small families and individuals with various cone and cone- rod dystrophy phenotypes. A missense mutation (E837D) was identified in affected members of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this is the first report of dominant mutations in this gene.      

Comparison between testosterone oenanthate-induced azoospermia and oligozoospermia in a male contraceptive study. IV. Suppression of endogenous testicular and adrenal androgens

Administration of supraphysiological doses of testosterone to normal men causes inhibition of spermatogenesis, but while most become azoospermic, 30-55% maintain a low rate of spermatogenesis. We have investigated whether there are differences in endogenous androgen production, of testicular and adrenal origin, which may be related to the degree of suppression of spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m. injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic, while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a specific testicular product, was reduced to <10% of pretreatment values, with no differences between the groups. Similar results were obtained for other markers of testicular steroidogenesis. Urinary and plasma adrenal androgens were also reduced during TE treatment: a statistically significant decrease in both (P < 0.001 and P < 0.05 respectively) was seen in the azoospermic but not oligozoospermic responders. These results suggest that testicular steroidogenesis is decreased to <10% by the administration of supraphysiological doses of exogenous testosterone. Differences in the degree of ongoing steroidogenesis in the testis do not appear to account for incomplete suppression of spermatogenesis, thus differences in androgen metabolism may underlie this heterogeneous response. A small but significant reduction in secretion of adrenal androgens was also detectable, the relevance of which is unclear.      

Sexuality in the climacteric years

Menopause is a time of anatomic, physiological and psychological changes that often influence in the sexuality of aging female. Being sexual functioning an important aspect of health and well-being, doctors should have an holistic approach reassuring about the possibility of treating the various symptoms. The central nervous system is an important target for sex steroid hormone; estrogen, progestagens and androgens are able to modulate several brain functions, and receptors for gonadal steroids have been identified in several brain areas. Because there is no test that physicians can make to assess sexual function, taking a sexual history is probably the most important aspect in the diagnostic and treatment of sexual problems. Hormonal transition with decreasing levels of estrogen and testosterone produces clinical effects, so women need to make adjustments for this period of life. Testosterone is an important component of female sexuality, and alterations in its circulating levels play an important role in psychological and sexual changes that occur after menopause. This is the reason why the research in identifying women who have a decrease androgen active should be aimed. Treatment may include education about sexuality and medical management of symptoms or problems interfering with sexual activity. Also treatment implications and the diverse aspects that may influence on sexuality in the climacteric years are discussed.     

Single dipole localization: Some numerical aspects and a practical rejection criterion for the fitted parameters

Summary There have been a number of attempts in the last years to localize the generators of brain electromagnetic activity, considering one current dipole as the source model. Single Dipole Localization (SDL) requires the selection of an optimization algorithm (OA). General aspects related with the selection, implementation and evaluation of some of the OA employed for SDL are discussed in this paper. Specifically the performance of two algorithms, those of Hooke-Jeeves and Levenberg-Marquardt, are tested by simulations. Suggestions for including restrictions to the dipole position and comments about some commonly used measures of the goodness of fit are given. Examples of erroneous implementations of these algorithms are also illustrated. A simple graphic rejection criterion, which can be easily used by inexperienced researchers, is introduced and tested in noisy and noise free simulations.The authors are grateful to Roberto D. Pascual Marqui for programming the Hooke-Jeeves algorithm.